The scenario is as follows: C: is the system drive, and the goal is to merge space from E: into C:.

There are a few complications:

• Only adjacent unallocated space can be merged
• E: must be deleted and converted to unallocated space before it can be merged into another volume (such as C:)
• Software installed on E: will have broken shortcuts and become unusable after the drive is moved

The process therefore involves roughly three major steps:

1. Back up / move data from E:
2. Expand C:
3. Fix software shortcut issues

Back Up / Move Data from E:

I had an empty D: drive dedicated to receiving the data from E:. Using copy/paste to move data is slow and cannot be resumed if interrupted.

Use the robocopy command instead — it’s reliable, fast, and supports resume:

robocopy E:\ D:\ /MIR /COPY:DAT /DCOPY:DAT /R:1 /W:1 /XJ

• /MIR — mirror copy (replicates the entire directory structure of E: to D:)

• /XJ — excludes junction points (prevents infinite recursion caused by certain junctions)

• /R:1 /W:1 — minimal retries on error, so it won’t stall for long

Note: /MIR will turn D: into an exact mirror of E:. If D: already contains important data that you don’t want overwritten, do not use /MIR.

Expand C:

First, download a partition manager to handle drive deletion and resizing. AOMEI Partition Assistant is recommended here because it comes with a built-in WinPE environment — expanding the system drive requires WinPE, and other tools may not include it.

Delete E:

Delete E: in AOMEI Partition Assistant to convert it to unallocated space.

Note: Although Windows’ built-in “Create and format hard disk partitions” tool also has a delete option, it may refuse to delete E: if programs are still running from it or for other reasons. Use AOMEI Partition Assistant to force-delete the drive.

After force-deleting E:, the system may prompt you to restart. After rebooting, a Performance Options window may appear (possibly because a manual system state refresh is needed after a forced deletion).

Go to Virtual Memory → Change, and select “Automatically manage paging file size for all drives.”

This Performance window can also be opened manually: search for View advanced system settings → Advanced → Performance: Settings → Advanced.

Move the Unallocated Space

The next step is to move the unallocated space to the right side of C: so that it becomes adjacent to C:. However, there is currently a Recovery Partition between them.

AOMEI Partition Assistant has a direct partition-move feature, but I implemented this manually instead:

1. First, expand the Recovery Partition to absorb the unallocated space on its left
2. Then shrink the Recovery Partition from the right, returning that space as unallocated on the right side

This effectively moves the unallocated space to the right of C:.

Merge the Space

Now extend C: into the unallocated space.

When expanding the system drive, you will be prompted that WinPE assistance is required. AOMEI Partition Assistant handles this automatically with its built-in WinPE. Simply confirm the operation — the computer will reboot automatically, enter WinPE, complete the resize, and then reboot again back into your normal system.

C: will now have the expanded capacity.

Fix Software Shortcut Issues

In “Create and format hard disk partitions,” right-click D: → Change Drive Letter and Paths, then reassign it to the letter E:.

This may fail with a “The parameter is incorrect” error — try restarting the computer to resolve it.

Once the drive letter is changed back to E:, all software should resolve its paths correctly and all application shortcuts should work normally again.